From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753710AbeBUKto (ORCPT ); Wed, 21 Feb 2018 05:49:44 -0500 Received: from terminus.zytor.com ([198.137.202.136]:41425 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752178AbeBUKtm (ORCPT ); Wed, 21 Feb 2018 05:49:42 -0500 Date: Wed, 21 Feb 2018 02:49:00 -0800 From: tip-bot for Josh Poimboeuf Message-ID: Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, jbaron@akamai.com, rostedt@goodmis.org, mingo@kernel.org, peterz@infradead.org, hpa@zytor.com, bp@suse.de, jpoimboe@redhat.com Reply-To: mingo@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, rostedt@goodmis.org, jbaron@akamai.com, bp@suse.de, hpa@zytor.com, jpoimboe@redhat.com In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] jump_label: Warn on failed jump_label patching attempt Git-Commit-ID: 5400c00440061515c5bda299c19b6e86b81be798 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 5400c00440061515c5bda299c19b6e86b81be798 Gitweb: https://git.kernel.org/tip/5400c00440061515c5bda299c19b6e86b81be798 Author: Josh Poimboeuf AuthorDate: Tue, 20 Feb 2018 11:37:52 -0600 Committer: Ingo Molnar CommitDate: Wed, 21 Feb 2018 10:11:39 +0100 jump_label: Warn on failed jump_label patching attempt Currently when the jump label code encounters an address which isn't recognized by kernel_text_address(), it just silently fails. This can be dangerous because jump labels are used in a variety of places, and are generally expected to work. Convert the silent failure to a warning. This won't warn about attempted writes to tracepoints in __init code after initmem has been freed, as those are already guarded by the entry->code check. Signed-off-by: Josh Poimboeuf Acked-by: Peter Zijlstra Cc: Borislav Petkov Cc: Jason Baron Cc: Linus Torvalds Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/de3a271c93807adb7ed48f4e946b4f9156617680.1519051220.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/jump_label.c b/kernel/jump_label.c index b717765..b2f0b47 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -367,12 +367,15 @@ static void __jump_label_update(struct static_key *key, { for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { /* - * entry->code set to 0 invalidates module init text sections - * kernel_text_address() verifies we are not in core kernel - * init code, see jump_label_invalidate_module_init(). + * An entry->code of 0 indicates an entry which has been + * disabled because it was in an init text area. */ - if (entry->code && kernel_text_address(entry->code)) - arch_jump_label_transform(entry, jump_label_type(entry)); + if (entry->code) { + if (kernel_text_address(entry->code)) + arch_jump_label_transform(entry, jump_label_type(entry)); + else + WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code); + } } }